The present invention relates to an apparatus and method of controlling an electric oil pump, and particularly relates to an apparatus and method of controlling an electric oil pump driving motor suitable when using a brushless motor for driving the electric oil pump which is disposed in a circuit of the electric oil pump.
There has been proposed a hybrid vehicle that is driven by a gasoline engine and an electric motor in view of improvement in fuel economy of a vehicle and environmental issue. The hybrid vehicle performs so-called idling stop control in which the engine is allowed to stop when the vehicle is stopped. Upon conducting idling stop, an engine driven mechanical pump is stopped, and a motor driven electric pump is actuated to supply oil to parts of the vehicle and allow next smooth starting of the vehicle.
A working oil that is used in the motor driven electric oil pump as described above has a viscosity variable in accordance with a temperature change. Due to variation in viscosity, a flow rate of the working oil is changed, and a hydraulic pressure is also changed. Therefore, Japanese Patent Application Unexamined Publication No. 2002-206630 discloses a drive control apparatus for an oil pump in which a working voltage for an oil pump driving motor is changed in order to vary a flow rate of the working oil.